The state of the 64-bit transition in iOS, and what’s left to be done

July just started, but the Apple rumor mill is already looking forward to September, the month when we tend to get new iPhones, a new iOS, and other refreshed Apple devices. Right now, the usual sources seem to think we’re getting new iPhone 6Ses that add Force Touch and faster modems but are physically identical to the current models, none of which should be particularly surprising. Yesterday, people digging through the iTunes 12.2 release found some evidence of new iPods, which would be a surprise—the lineup’s last significant update came in September of 2012.

Supposing Apple replaces the iPhone 5C and gives us a revamped iPod Touch at some point between now and this fall, Apple could be in an interesting position: every iPhone, iPad, and iPod the company sells could be using 64-bit hardware and software. It already discontinued the last 32-bit iPad in June.

Since we haven’t checked in for a few months, this prompted us to take another look at the state of 64-bit support in the iOS ecosystem. How is the hardware and software shaping up, and when can we expect iOS to go 64-bit-only as the Mac did a few years ago?

Hardware support and a 64-bit timeline

First, a broad outline of the major milestones in the journey to 64-bit. Just to recap: 64-bit support in mobile devices is less about the 4GB RAM limit that drove the transition on the desktop and more about the architectural enhancements and performance improvements included in the ARMv8 instruction set. 64-bit iOS CPU benchmarks run around 30 percent faster than 32-bit benchmarks running on the same hardware.

• September 2013: Apple introduces the iPhone 5S. Its Apple A7 chip makes it the first 64-bit iDevice. iOS 7 is the first 64-bit version of iOS, at least when running on the A7.
• October 2013: The iPad Air and what is now called the iPad Mini 2 are introduced. Both include the Apple A7 SoC.
• March 2014: iOS 7.1 is released. It resolves most of the memory-related crashes in 64-bit iOS.
• September 2014: The iPhone 6 and 6 Plus are released. Their Apple A8 chip is Apple’s second 64-bit SoC. Apple stops selling the iPhone 4S, making the iPhone 5C the last of the 32-bit iPhones.
• October 2014: The iPad Air 2 and iPad Mini 3 are released. Both include 64-bit chips (the A8X and A7 again, respectively). The fourth-generation Retina iPad, which had been on sale for $399, is discontinued. The original iPad Mini is the last of the 32-bit iPads.
• February 2015: All new apps submitted to the App Store must include 64-bit support.
• June 1, 2015: All app updates submitted to the App Store must include 64-bit support.
• June 19, 2015: Apple quietly discontinues the original iPad Mini. The only 32-bit iPads Apple now sells are refurbished.

The hardware transition is nearly complete, which is sort of astounding given that the first 64-bit iDevice came out less than two years ago. In all likelihood, the iPhone 5C will fall off the end of the lineup when new iPhones arrive. The iPad is already there.

The two major holdouts are the iPod Touch and the Apple TV. Rumors about a new version of the set-top box have been lingering for years, and it has to happen sometime, but in any case it’s clearly in the works.

As for the iPod Touch, well, those iTunes product shots don’t give us a lot to go on. Assuming the renders are accurate and not just some Photoshop mistake (a common occurrence), they don’t include the little camera loop that the fifth-generation Touches have, suggesting the potential for other internal changes. That’s all we have to go on, aside from the fact that it just makes sense to move the Touch away from the aging 32-bit A5 and its 512MB of RAM (iPods aren’t big sellers anymore, but iPod Touches are useful as development devices or as pocket computers for non-smartphone users).

A new, 64-bit iPod Touch based on the Apple A7 would make the most sense at this point. That chip plus the 4-inch screen are old enough that they could be sold profitably for $200 or $300, and it would be a significant upgrade for the current Touch even though the A7 isn’t exactly cutting edge these days.

The app ecosystem

Let’s trot this out one more time—last May we threw together a quick list of common apps from major companies to see which supported 64-bit, ARMv8 operation and which didn’t. We checked again in September when the iPhone 6 and 6+ came out, and in October when Apple announced the 64-bit submission requirement for new apps. Even in October, less than half of the apps we tried were running in 64-bit mode. How about now?

What a difference a year makes. These apps are all in active development, and it looks like the submission requirements are working as intended. Gmail is the only 32-bit holdout, which makes sense since it hasn’t been updated since March of 2015—one assumes Google’s development efforts have mostly been refocused on Inbox.

So the app ecosystem is there. The hardware is just about there. What’s left?

Legacy support

The question with any transition like this is when, exactly, to cut 32-bit devices loose. To date, OS X is one of the few operating systems that has actually managed to make a clean break, owing mostly to Apple’s tight control of its hardware.

Windows 10 will still come in a 32-bit version. Most major desktop Linux distributions still ship a 32-bit version. Android 5.0 included native 64-bit support but the hardware was slow to follow, and some phones that technically support ARMv8 operation still run 32-bit Android anyway. All of these operating systems support a much wider range of hardware than Apple’s software does—much of it cheaper, slower, older, or some combination of the three—but slow transitions are the price you pay for that compatibility.

We don’t think 32-bit iOS support will disappear anytime soon. iOS 9, due this fall, supports all the same 32-bit Apple A5 and A6-class devices as iOS 8 does. The A6 isn’t yet showing its age to the extent that the A5 is, so it could conceivably hang around for another year after the A5 rides off into the sunset. All of Apple’s development tools are set up to make it easy to ship universal 32-bit and 64-bit binaries, and iOS 9’s App Thinning feature should mitigate one of the biggest downsides of supporting universal apps.